Nonlinear dynamic model of air spring with a damper for vehicle ride comfort

The air spring component with a damper inside is widely used in the commercial vehicle as a vibration isolator. The nonlinear dynamics of the air spring component is important for full vehicle ride comfort evaluation. This paper aims to develop a mechanical model of the air spring component which can reproduce the air spring characteristics correctly. The proposed model consists of three split force branches in parallel describing the nonlinear elastic characteristics based on thermodynamics, the asymmetrical hysteresis and amplitude dependence by variable Berg’s friction, and the frequency dependency with four-parameter fractional derivative model. The air spring component bench tests are conducted, and the procedure of model parameter identification and model verification is presented. The nonlinear dynamic responses of the proposed model are investigated under a large amplitude excitation and different pre-compressions/pre-elongations by comparing with the Berg’s model which uses a linear elastic force element. Additionally, the proposed model and the Berg’s model for the air spring component are separately integrated into a full vehicle multibody dynamic model to evaluate the ride comfort as application for further verification through the co-simulation method using MATLAB/Simulink and MSC.ADAMS. The proposed model is verified to be more accurate than the Berg’s model through comparison with the full vehicle ride comfort test results.